1. Field of the Invention
The present invention relates to a door weather strip for providing a seal between a door of a motor vehicle and a door opening portion of a vehicle body.
2. Description of Related Art
FIG. 1 shows a door seal structure including one example of a conventional door weather strip. As shown, a door weather strip 10 is attached to an outer periphery of a door frame 12 of a door 14, and an opening weather strip 16 is attached to a flange 18 projecting from a door opening portion 20 to provide a seal between the door 14 and the door opening portion 20. And a door glass run 22 is attached in a channel 24 secured to an inner periphery of the door frame 12 to provide a seal between a door glass 26 and the door 14.
The door glass run 22 has a generally U-shaped cross-section, and includes side walls 28 and 30 and a bottom wall 32. Seal lips 34 and 36 project from open ends of the side walls 28 and 30 for contacting and sealing the door glass 26.
The opening weather strip 16 includes a trim portion 38 having a generally U-shaped cross-section and a tubular seal portion 40. The opening weather strip 16 is attached to the flange 18 provided in the door opening portion 20 with the trim portion 38, and when the door 14 is closed, the door frame 12 contacts the tubular seal portion 40 to provide a seal between the door 14 and the door opening portion 20.
The door weather strip 10 includes a base portion 42, a main seal 44 and a seal lip 46. The main seal 44 and the seal lip 46 are formed on the upper side of the base portion 42 integrally therewith. The base portion 42 is fitted in a retainer 48 secured to the outer periphery of the door frame 12. When the door 14 is closed, the seal lip 46 contacts the door opening portion 20 to seal the gap between the door frame 12 and the door opening portion 20. And the main seal 44 contacts the door opening portion 20 on the inner side of the contacting position of the seal lip 46 to seal the gap between the door 14 and the door opening portion 20.
In the conventional door weather strip thus arranged, when the door 14 is closed, a peripheral edge of the door frame 12 presses the seal lip 46 against the door opening portion 20 to bend the seal lip 46. Consequently, depressions are formed in the seal lip 46 to deteriorate the appearance thereof.
When the motor vehicle is running at high speeds, the door 14 may be drawn and displaced outwardly due to the pressure difference between the interior and the exterior of the vehicle body, etc. Consequently, a tip end of the seal lip 46 may separate from the door opening portion 20 and project outwardly of the vehicle body, thereby degrading the sealing properties.
Accordingly, for providing a good appearance free from depressions which have been encountered with the seal lip of the conventional door weather strip, and for preventing the tip end of the seal lip from being drawn outwardly upon running of the motor vehicle at high speeds, as shown in FIG. 2, there has been proposed to provide a seal lip 50 having a generally hook-shaped cross-section (Publication of Japanese Utility Model application No. Hei 3-10922, FIGS. 2 and 3, etc.).
The seal lip 50 having a generally hook-shaped cross-section, however, may have the following problem. Namely, when the door 14 is opened and closed, the position of a tip end of the seal lip 50 may displace in a width direction of the vehicle body. When the door 14 is closed, and a middle part of the seal lip 50 contacts a roof moulding 52 attached along a roof-side of the door opening portion 20, the seal lip 50 may be deformed with the pressing of the roof moulding 52 to form depressions and projections between the door frame 12 and the roof moulding 52, and to separate the tip end of the seal lip 50 from the door frame 12 and project it outwardly of the vehicle body. At this time, a base of the seal lip 50 may be also deformed, whereby the seal lip 50 separates from the roof moulding 52 to degrade the sealing properties thereof.
Alternatively, a tubular part having a generally rectangular cross-section may be substituted for the above-described seal lips (Publication of unexamined Japanese Patent application No. Hei 11-34672, FIG. 1, ex.).
However, in this case, the following problem may occur. Namely, when the door is closed, a corner of the tubular part having a generally rectangular cross-section contacts the door opening portion so that walls of the tubular part on both sides of the corner may deform to increase the door closing force. In addition, depressions may be formed between the door opening portion and the door frame due to the deformation of the tubular part, thereby deteriorating the appearance therearound.